SELECT Customer, SUM(Consumption) AS Total_ConsumptionFROM Table_NameGROUP BY CustomerORDER BY Customer

=============================================================If you are using SQL SERVER 2012, then you can also do:SELECT Customer, SUM(Consumption) OVER(Partition by Customer ORDER BY Customer) AS Total_ConsumptionFROM Table_Name

SELECT Customer, SUM(Consumption) AS Total_ConsumptionFROM Table_NameGROUP BY CustomerORDER BY Customer

=============================================================If you are using SQL SERVER 2012, then you can also do:SELECT Customer, SUM(Consumption) OVER(Partition by Customer ORDER BY Customer) AS Total_ConsumptionFROM Table_Name